In 2007, Spain launched a program to develop Ingenio, the nation’s first-ever optical imaging satellite tv for pc. Quick ahead 13 years, 200 million euros, and immeasurable work by engineers and the project was finally ready to be launched as of last week. Sadly, this undertaking didn’t reap success as undertaking members had hoped.
Ingenio: the 200 million Euro undertaking that failed. Picture from El País
About eight minutes after launch, the management middle observed that the satellite tv for pc was shifting away from its established path. Then, the satellite tv for pc misplaced management altogether, ultimately failing and crash touchdown in a distant space of the Arctic. After analyzing the telemetry information, the workforce decided the reason for failure— and it was one thing out of an engineer’s worst nightmare.
The Offender? Erroneously-Assembled Cabling
The cables related to the engines that managed the trajectory of the rocket had been plugged in backward. Not a design flaw, however an meeting error.
Whereas quite a few testing procedures ought to have caught the error, one easy method to have prevented the state of affairs was to make use of cables with distinctive connectors on each ends of the cable. Assuming that fixed impedances may be maintained with two connector varieties and that the insertion losses are stored to a minimal, this answer would’ve made it unimaginable to put in the cables within the flawed path.
This picture depicts a small, cheaply-designed transformer Within the early 20th century, EEs used to design the windings and select the kind of wire that labored greatest for a design. Now, we use thinner wires as a result of they’re cheaper—however motors burn them out sooner. EEs are additionally much less conversant in the ins and outs of wiring. Picture used courtesy of the Edison Tech Center
This incident speaks to the need for engineers to not solely be consultants on the extra complicated points of circuit design but in addition to attune an eye fixed for element with seemingly prosaic expertise, like cable meeting and connectorization.
The information can educate us one other helpful lesson as effectively. Normally, how does cabling have an effect on design?
Cabling Impacts Design
Engineers are confronted with a number of considerations when selecting cables for electrical designs: What kind of wire ought to I exploit (for instance, braided, stranded, or stable)? What materials wire ought to I go for—aluminum, copper, or gold? How is the wire insulated?
For the sake of this text, nonetheless, we’ll solely discover two basic causes that cable choice can impression design: EMC and transmission line results.
Cabling and EMC
With respect to EMC, one thing to keep in mind when selecting cables is the fact that all cables are antennas. By the legal guidelines of physics, all conductors create electrical and magnetic fields from the cost and present via them. For that reason, cables may be the principal means by which alerts trigger radiated emissions and exterior fields contaminate alerts (susceptibility and immunity).
Conductor size vs. antenna effectivity. Picture from Keith Armstrong
Cabling and Transmission Line Results
Transmission line results happen when interconnect lengths grow to be higher than wavelengths of the transmitted sign. Since bodily cables are typically the longest interconnects in electrical designs, they’re most liable to transmission line results.
An vital consideration on this regard is the attribute impedance (Z0 = √L/C ) of a line. These impedances are unavoidable, so to mitigate their results we’ve got to decide on cables that both have Z0 stored fixed over the whole size of the interconnect or match the load and supply to the attribute impedance of the road.
That is why RF and all EMC check gear use controlled-impedance 50-ohm transmission line cables and connectors.
Consideration to Element Issues
Though cable choice and meeting are sometimes neglected points of design, these particulars can have big impacts on a system’s operation. Sure, the satellite tv for pc incident in Spain was an excessive illustration of this idea, however it might probably function a helpful reminder to engineers to reexamine much less “glamorous” skillsets and decide to higher consideration to element.
Generally, probably the most consequential design failures come all the way down to easy errors. Have you ever ever heard of such a mistake? What takeaways can the EE group internalize from such incidences? Share your ideas within the feedback beneath.